Method of and apparatus for bending filaments



T. R. GRIFFITH METHOD OF AND APPARATUS FOR BENDING FILAMENTS Filed Oct.10 1924.

Patented Nov. 16,1926.

UNITED" STATES PA,.TEN T, ,QFHCE. 4

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METHOD OF AND APPARATUS. FOR BENDING FILAMENTS.

- Application flledIOctobernlO, 1924. SerialNo. 742,756..

This invention relates to .a method and apparatus for bending andforming refractory material and particularly refractory: filaments suchas are used in high power 6 electron discharge devices.

It has for an object to facilitatethe transformation of a .lon length ofrefractory wire into a desirahle form, such as M.- shaped or V-shapedfilaments for the above purpose.

This object is attained by providing a metallic standard having a handoperated plunger which insulatingly supports a plurality of electrodejaws and a bending frame which carries a measuring voke and: a removable lnsulatlng plate. A filament wire is laid in a slot in theinsulating plate and the lunger lowered until it contacts with thelament wire, whereupon a circuit isestablished between the electrodejawsand the portion of the wire between. the jaws is heated and bent overthe insulating dplate. The bent filament wire is remove from the frameand the bent portion placed over the ,5 hook on the measuring yoke, theparallel strands of the wire being laid in "the slots of the insulatingplate andathe plungpr again lowered to bend the wire to form. t efilament in the desired shape in which it 80 will be used in an electrondischarge device. A filament formed in this manner can be attached tothe filament supporting structure in the device without any truing up ormeasurements of the length of the strands between bends. Y

Referring to the drawin s: Figure 1 is a side view 0 the bending jigmade in accordance with this invention. Fig. 2 is an enlarged. sectionalfront view with the filament wire held: in position.

Fig. 3 is the same as Fi 2' but showing the plunger in its operateposition.

Fig. 4 is an enlarged plan view of a section of the 'ig illustrating thesecond step of the hen ing operation.

ig. 5 is a front view of Fig. 4 showing the bent filament indottedlines, and.

Fig. 6 is the com an apertured extension bent at right angles lete bentfilament readyto be inserted in a igh power electron disto the standard.through whichv bolts are passed to fasten the standard to a base or workbench 2. An. apertured metallic block 3.. is fastened to the standard 1adjacent the upper end thereof and forms. a" guiding member -for theplunger rod 4, which. is attached to the hand operated lever 5 carried'atthe upper end of the standard 1. A n

slot 6 is provided on one longitudinal surface of the plunger rod 4 anda set screw 7, fastened through the guidemember 3, limits the upward anddownward movement of the plunger rod 4. An integral bifurcated extenslon8 on the lower end of the plunger 4 is provided with apertures toreceive a locking screw to su port an insulating block 9, preferablv oflavite. The insulating block 9 is 0 such formation as to provide a rigidcontinuation of the plunger I 4 and insulatingly su ports metallicelectrodes 10 and 11 whic lower end of the insulating block 9. Theelectrodes 10 and 11 are supported from the block 9 by means of a screw12 passing through the electrodes and the insulating block 9. Theelectrode 10 is insulated from electrode 11 by having a larger borethrough which the screw '12 passes and being in sulated from the screw12 ,by insulating washer 13. Suitable electrical connections 14 and 1 5are attached to the electrodes and connected to any desirable source ofpo wer. The contacting surfaces of the electrodes 10 and 11 are curvedinwardly to prevent the electrodes cutting the filament wire in. thebending operation to be described hereinafter.

A rectangular metallic frame 16 having an extension 17 bent at rightangles to the plane surface of the frame is arranged in an edgewiseposition with respect to the plunger rod 4. and attached to the frame bymeans.

of bolts and nuts. The frame 16 is positioned on the standard in such amanner that when. the'plunger is lowered the electrodes 10 and. 11 passon either side of the edge of the frame 16. A portion of the frame iscut away to provide a seat for insulating plate 18,. which is preferablyof lavite, the plate being provided with a rounded edge havingindentations 19. A pair of metallic guiding strips 20 are attached tothe frame on one side of the cut portion, the upper ends are carried atthe i of the strips projecting above the edge of the frame and one sideof the guiding strip ,1 projecting over the edge of the cut portion ofthe frame. A pair of similar guiding strips 21 are attached to the frameon. the opposi with t e strips form a pocket for the insulating plate18. This construction pro-' vides suitable means for replacing thensulating plate 18 in the event of breakage or 22 and 23 through whichpins 24 and 25 extend to carry movable bearin s 26 and 27. The movablebearings 26 and 2 are be descri bed. A. filament wire I tory material,such! as tungstem'of suitable length to form a filament, is laid acrossthe bending frame 16 and positioned in one'of "the slots 19 in theinsulatin plate*18l'-- The lever 5 is operated, where ythe plungersu'lating' plate positioned in said frame,"re'-I j 11 contactwith thefilament wire A. This" v o ratiorigiestablishes a' metallic circuit trou h the'electrode jawlO, a portion of the lament wire and electrodejaw 11, whereby the portion of the filament wire between the electrodejaws is heated to a red. 1 glow, andpressure is then applied to theagain lowered until. the elect with the strands B and C and a circuites-' tablished to heat the portions-of'the strands between the electrodejaws. The plunger is, further '0 erated to bendthefilament wirev overthe rame and the pl I to removekthe filament wire m the bend-. ;W be bswmgmg 3 provided with vapertured extensions 28 and 29 to which isattached a measuring yoke 30 by means of rivets." A hook member 31pro-;: jects from the upper surface of the yoke 30 and is positionednear the converging point of the arms of the yoke. The normal positionof the-yoke is generally in a substan-.

tially parallel plane'with the frame 16 but in its operated position isswung up at right angles to the frame and lies in a'plane sub-'stantially the same as the edge of the frame; This arrangement providesa jig which may be used for bendin both V and M shaped filaments sincethe oosely' pinioned yoke is only used when the M shaped filament is desired.

The operation of thebendingiigwill how is lowered and the electrode jaws10 and plunge'ritd bend the filament wire over' the frame'to completethe first operation. The

' a standard, "a bending frame attac ed to filament wire'is removed fromthe frame and comprises two strands B and C insubstantiallglparallel-relation." The bent portion of the anient wire ishooked over the pin 31 (in ,the 1measuring joke 30 and the yoke swung nto a plane approximately the same as't e edgeofthe bending frame, and

the strands B and C laid in the slots 19 in the 'insulatinggplate 18.The lunger is escontact side of the cut portion and together trodescarried bv 'said vtached to said stan of refrac- 5 yoke carried by saidframe. 1

r withdrawn ing frame. The filament wire nowcomprises four strands, B,C, D' and E,"as shown in Fig. 6, and is formed into the desired shape inwhich it will be used. in a high power electron .discharge device.

Althoughh-this invention has been d-F scribed with reference totheibendin and;

cation forming of a highlyirefractory ment it is within the; V to bendother forms'of'refra l1 and other metals in wire form' -in whi "desiredto electrically heat" andbend portions of the Wire to form desirableshapes'and configurations. t: a. H

\Vhat is claimed is 4 1. A filament; forming -apparatus c-om prising astandard, amovablelunger'attached to saidstandarch-"a plura ity ofelecglunger, a frame atard, a removable grooved. insulating plate 1.carried by), said frame, and a yoke looselymounted on said;- am'ent' inadjuste'dj position on said plate. 4

frame for holding the fi 25A filament bending device I a standard, -alever attached-to said stan ard, a" plunger carried by'said lever, guid-7 ried by said insulating block, a metal-frame arranged edgewise withres act to said plunger and attached to sai standard, a removableinsulating plate,"means on said frame to support said plate, andaswinging 3. A filament bending device comprisin ard:- -intermediate theends thereof, in-

taining means for said plate attached to a standard, aframe attached tosaid stan said frame, bearings carried by'said frame,

a swinging yoke, supported from said bearin a guide block attached tosaid standar agplunger slidably mounted in said lock,-{ ineansforoperating said lunger, anda-fplurality of metallic electrod dsinsulatingly supported by said plunger.

4. A filament bending device com rising said standard, -an insulatinplate carried by said frame, said platebem'gadapted to receive afilament wire to be bent,- a. slidable plunger carried by said standard,,aniinsuating block carried by'said plugger, and :a lura ity ofelectrodes support I b said lock, whereby the contact of saifelec 5. Afilament bending device comprising a standard, abending frame attac dits I said standard, an insulating plate carried-Q} by said frame, saidplate adapted to receive -'11 supported at either side of said plate, apin carried by said yoke, said pin being adapted to carry the filamentwire, said yoke being swung in the same plane as the edge of saidinsulating plate, the parallel strands of the filament being laid onsaid insulating plate, anda slidable plunger carried by said standardand adapted to apply pressure to the filament wire whereby the filamentwire is bent in the form in which it will be used in vacuum tubes.

6. The method of bending and forming a refractory wire which compriseslaying said Wire on a bending frame having a swinging yoke, lowering aplurality of electrodes in contact with said wire, applying pressure toportions of said wire to bend said wire over said frame, removing thebent wire from the frame, attaching the bent portion to said yoke,elevating said yoke to the plane of the edge of the frame, positioningthe two strands of the bent wire across said frame, and thereafterlowering the electrodes on said strands to bend said strands over saidframe.

7. A bending device comprising a standard, a frame. attached to saidstandard, said frame having a removable insulating plate to receive awire to be bent, a plunger mounted on said'standard, a plurality ofelectrodes carried by said plunger cooperating with said plate and amovable yoke for positioning said wire on said plate.

8- A bending device comprising a stand ard, a frame attached to saidstandard, said frame being adapted to receive a wire to be bent, aplunger carried by said standard, a plurality of electrodes supported bysaid plunger and adapted to heat and bend the wire over said frame, saidelectrodes passing on either side of said frame.

In witness whereof, I hereunto subscribe my name this th day ofSeptember, A. D. 1924.

THOMAS R. GRIFFITH.

